An arc furnace is used to produce liquid metal, generally steel. The liquid metal is produced from scrap metal or reduced iron together with further additives. At present, an arc furnace is operated virtually independently of the solid material to be melted in the arc furnace. The arc furnace is therefore operated, in particular an arc is set, statically, that is to say on the basis of a fixed process plan, with respect to the material to be melted supplied to the arc furnace. This leads to the arc furnace not being operated optimally from technical and financial points of view. For example, charging times or tapping times are not chosen optimally since either too long a time period is allowed for charging with new solid material, or charging is already stopped, even though not enough solid material has yet been melted in the arc furnace.
Laid-open specification DE 10 2005 034 378 A1 discloses a method for determining a condition of the content of an arc furnace. However, it remains unclear how a method such as this according to the laid-open specification is intended to operate.